Dual core: 1@100% but no processes

Dell Inspiron 6400
November 19, 2008 at 10:35:50
Specs: Windows XP Pro SP2, Intel Core 2 T7200 2GHz /
Yesterday something strange started happening. My computer's performance took a massive nosedive.

Simple things such as sound playback and mouse movement are very choppy/laggy. Overall performance of applications is at about 10-20% of what it was before yesterday.

Close inspection of Windows Task Manager shows one core at near 100% CPU usage whilst the other remains relatively idle. Process information shows no processes using up any large amounts of CPU. There is plenty of free RAM available.

Furthermore, upon restart of Windows XP, I am now told I have made significant hardware changes and that I must reactivate XP within 3 days.

Using Diagnostic Startup (via msconfig) yields the same problem.

When I boot using a Ubuntu Live CD the core/CPU usage problem does not appear to manifest itself (that is, I can play video/surf the web/do lots of other stuff all at the same time without any performance hit or one core maxing out).

Does anyone want to guess at what the problem might be? Would it be an XP software issue or a hardware fault? Is there a way of testing each of the two CPU cores in Ubuntu/Linux?

See More: Dual core: 1@100% but no processes

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November 19, 2008 at 10:48:39
Sounds like some sort or virus or malware infection....

"If my answers frighten you then you should cease asking scary questions" - Jules Winnfield (Samuel L. Jackson) in Pulp Fiction

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November 19, 2008 at 11:08:37
I didn't even consider that as a possibility because the problem was still occurring in Diagnostic Startup mode.

However, I will try and run a virus/spyware/malware scanner over the hard drive anyway. Thanks for the suggestion.

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November 19, 2008 at 13:45:39
Yeah i agree with jam you have somethong on your system, either a virus, trojan, malware, ad-ware or spyware. Normally when your processor is running at 100% for no reason it's caused by one of those 4 attacks that i mentioned. Something nasty got into your system if it is causing your OS to prompt for reactivation, I wouldn't be surprised if it was some kind of key logger program.

If it's broke, then blow that sucka up!

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Related Solutions

December 15, 2008 at 22:40:07
Just want to add that I am having the exact same issue on an Acer Aspire One with an Atom processor.

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December 20, 2008 at 05:19:44
I've had a similar problem that just manifested itself last night. Turned off my PC and passed out, when I turned my PC back on core 1 was stuck at 100%.

Rebooted +F8 into safe mode, no issues core 1 is fine. (keep in mind safe mode uses windows graphics drivers NOT ones applicable to your GPU)

I reinstalled OS (Server 2k8) hoping that would fix the problem. At first it did, but as soon as I reinstalled nvidia's 180.48 driver for my 2x 9800GTX sli setup core 1 went back to 100% usage. Uninstalled the driver and it is back to normal. I'm installing 178.24 forceware atm to see if a driver rollback will fix it. Will update if it does.

Ok, rollback did nothing. Tested video cards, looks like one has died.. will test further.. but if you have any other cards to test your system with.. give that a shot. With just the one good card in I'm not getting any problems with core 1 constantly at 100% any more.

Edit: narrowed it down to the 3rd sli slot on my board, apparently it just up and died. if you are running an sli setup try it with only the one gpu hooked up.

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January 17, 2009 at 01:02:45
UPDATE: Still having to work with this annoying oddity. However, I found this forum thread which might help:


Please read the bit about clicking View->Show Kernel Times in the Performance tab of Windows Task Manager. Using this information, I am now able to establish that the maxing out of the CPU is all due to this "Kernel Time".

In that forum one of the members disabled his/her NIC and the maxing out has stopped!

This should now help in getting closer to the source of the problem...

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